"External crosstalk"-threats to IDC Rooms

With the increasing application of Cat 6a and Cat 6a, many communication data centers have not upgraded CAT6A and CAT7 cables, according to industry experts, the old cables are still used to maintain the network operation. For these IDC Rooms, there is little room for upgrading their networks.

Four pairs of wire cores in the same cable may leak some energy to other wire cores due to electromagnetic coupling. This crosstalk is called "external crosstalk", which not only interferes with signal transmission of adjacent wire cores, it also interferes with signals sent from other external cables of the cable. Because the cables of the same manufacturer are usually used during cabling, the twisting rate of the geometric line pairs of the cables of the same color is almost the same, so the interference between the cables of the same color is particularly serious, the degree of crosstalk increases as the signal sending frequency increases.

Because it is a type of noise signal, reducing external crosstalk is a measure to reduce the signal-to-noise ratio (S/N) of communication performance. Compared with traditional crosstalk, external crosstalk is a more headache than traditional crosstalk, because it is different from single-cause interference signal crosstalk, which is related to the protection of Network cables, this interference cannot be handled by using the DSP of the network device, so it will directly affect the signal stability.

For servers and other devices in the data room, external crosstalk is like a ghost. crosstalk between different cables is a threat of communication. crosstalk between different or identical cables can damage the network, due to the increasing communication requirements of data centers, the corresponding network wiring is also increasing in a large scale. The problem of external crosstalk is becoming more and more serious.

In cat6 and cat7 cable shielding, the cable's own shielding structure can usually weaken or eliminate ANEXT, greatly reducing crosstalk in the data center. However, the traditional IDC still relies on cat5 or cat6 cables. Due to the structure of the cable itself, it does not provide adequate protection for external crosstalk. Many old data centers are adding more devices to increase the information throughput, but cat5 or cat6 cables are still used for communication cables. Upgrading the network requires downtime, re-deployment of communication lines, and route changes. It is difficult to estimate the cost, resources, and time required.

"If there are too many crosstalk, the signal transmission error rate will increase, and extend the network response time and reduce the network throughput ". Rosydney said that when a data packet is transmitted through a cable, the crosstalk will cause packet loss. According to the standard, the communication data packet will be resent, thus affecting the actual data throughput. When packet loss occurs, the data communication capability may decrease or even the network is interrupted. However, external crosstalk is a precaution.

"In the equipment room and office area, cables of varying quantities are usually bundled together. Bundled cables may be placed in a pipe or trough. The cables in one bundle will affect the crosstalk of the cables in other cables. This type of crosstalk) is particularly evident in unshielded systems. As long as you select a suitable cable and do not lay other high-voltage power cables or high-power wireless transmitters around the communication cable, external crosstalk can be reduced.

On the other hand, when wiring, you should be aware of preventing external crosstalk and avoid cables from being bundled together too much. In the IDC room, customers with conditions can install shielded cables. cables with external shielded layers can prevent external crosstalk from entering and be isolated from each other. This effectively reduces the impact of external crosstalk.

Bloor research in the UK. tony, UK chief analyst, said cat5 cables were a common data center solution in the early days. In general, foreign crosstalk would not affect much unless managers were in the early stages of IDC construction, without good planning, devices and cables are constantly added after the IDC is built, so that the layout of the IDC exceeds the communication limit, and external crosstalk will also increase, the increase in external crosstalk makes IDC Rooms more dangerous.

With the increasing application of information communication systems. Communication between different network platforms is getting closer and closer. External crosstalk has become a part that cannot be ignored. After all, it is not as intuitive as other crosstalk tests. If you do not want to disturb your data center, you need to solve this problem as soon as possible.

An effective way to prevent ANEXT is to have a sense of advancement and plan well at the early stage of data center construction. First, try to avoid additional secondary cabling for the data center in the future. Be aware of risks to prevent ANEXT. Select a suitable cable to avoid the impact of the cable on the data center. As a result, the data center server and other devices cannot work normally.

In the construction of the data center, the more severe the crosstalk problem is when cables of poor quality and low category are used, as well as non-standard construction techniques.